Cookin’ with the Sun, Solar Box Cookers for Everyday Use

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Greetings from Ravi. First off, realistically, I’m blogging this one for the sunnier parts of our lands – solar cooking is a very practical, easy and nutrition-enhancing cooking method but, of course, you need pretty good sunlight. 3 years ago I researched and built and experimental solar cooker based on what I felt was the most practical design I could find – a “box” style cooker, one that was stable, large enough for full meals (and more) and effective as a potentially daily use cooker.

 

Barbara Kerr and her Sustainable Solar Creations

Barbara Kerr, a sustainable solar living advocate, did quite some pioneering of solar cookers, ultimately installing her design in the south side of her house for easy access. More on Ms. Kerr here: http://solarcooking.wikia.com/wiki/Barbara_Kerr  I am indebted to her basic design and inspiration. I altered the design to be freestanding and to rotate easily on a lazy susan mechanism for tracking the sun.

Who can Sun Cook Often

Our 3 year experiment has melted into a way of life – we cook 70% of our meals in the solar cooker as well as using it for sanitizing dish rags or whatever to sun-drying tomatoes and fruit. Of course – we are in New Mexico – land of the sun – but statistically, well over 1/2 the US could reasonably use solar cookers to their advantage.

southwest is best of course...

Cooking in a Solar Cooker

I’m not going th discuss the full range of solar cooker styles.  There are many innovative ones, but my experience and concern is for a cooker that can be mounted and used every day with as little attention as possible.  It’s just there and ready.  Only one style can really be made that convenient – the Solar Box Cooker.

Almost everything can be cooked well in a solar box cooker – the heat range on a sunny day is hotter than a slow cooker but not quite as hot or consistently hot (except on a cloudless day) as a conventional oven can potentially be. Inside the cooking pots the heat ranges from mid-200 Fahrenheit to mid-300’s. Potatoes cook in hours, chickens and meat actually brown in 3 to 5 hours. The cooking does not dry out the food when enclosed in a black pot with a little water, and the slow-ness imparts tenderness in every dish without robbing any flavor and as many nutrients as fast, hotter cooking. Even in the dead of winter with sub-freezing temps, using the full day of sun from 10am to 4 pm, you can cook a whole chicken and fixings that will brown on top ready to eat..

The different “hot box” approaches to Box Solar Cookers

There are 2 basic principles at work here and different solar cookers emphasize one or the other.  First of all you have the “greenhouse” effect ( http://en.wikipedia.org/wiki/Greenhouse_effect ).  By building a glass covered box, the inside of the box will reach substantial temperatures.  The second principle is that dark colors absorb all wavelengths of sun.  This is the reason for black cooking pots.  We have had great success with simple  enameled camping pots (and this camping pot as well) spray painted flat black – inexpensive and more importantly – non-toxic (DON”T use aluminum or non-stick cookware!) Of course, if you want to invest in the best (and still not too expensive) then cast iron dutch ovens are excellent (spray paint these flat black as well).

Here is where the 2 basic kinds of box solar cookers diverge.  One style colors the inside of the box black in an attempt to increase the box temperatures to cooking levels – 300+ degrees.  The “problem” with this kind of box solar cooker is that it cannot be too big inside unless it were to have massive reflectors – the surface area of the glass over the box lets in nowhere near the energy needed to achieve good cooking temps, thus large floppy and cumbersome reflectors must be attached. It also suffers when not accurately aimed at the sun that will travel gently across the sky every minute (lots of re-adjusting during the day). There is also the problem of what material to line a box with that will get to 300+ degrees – plastics? (off-gassing. deforming), metal? (heavier, costly), tinfoil covered cardboard? (low durability).  The less stable the components, the easier wind and weather can trash the cooker.

The other box cooker choice, in my view, is the better.

A solar box cooker with a fairly big box and glass covered opening angled towards the sun that operates on the “greenhouse” principle will get reasonably hot (200+ degrees) with stable-sized reflectors. The cooker is then lined mostly with reflective material and inside it are placed black cooking pots with food.  The ambient air temp around the pots is +-200 degrees, however, all the reflected light that bounces in and around in the box is then absorbed by the cookware increasing the cooking temperatures substantially (to 300+).  This design reduces the need for special high-heat resistant (costlier) materials in the box design and also allows for a larger cooking space. The box works together with the black cookware to get the job done. Finally, tracking the sun is much less critical since the light “focus angle”  is not so critical to achieve higher temperatures within the pots themselves.

Our SUN GOD Solar Cookers

Jack and I (Ravi) have teamed up on to produce SUN GOD Solar Cookers and for those of you in drivable distance to central New Mexico. We are building  hi-performance reflective box cookers for delivery to our region around Albuquerque and Santa Fe New Mexico.  We’re building them one-of-a-kind from recycled materials and sturdy enough to sit out in our New Mexico weather. For more information please visit our website. http://www.solarcookersnewmexico.com/

Commercial Solar Cookers Available

Lots more can be said for solar cooking – convenience, ease and less pan clean up (a whole stew in one pot) not to mention the energy is **free**!  As for available solar cookers – well – the DYIer’s out there can readily find build-it-yourself solar ovens – most not very long-term use as they are made out of cardboard and tinfoil. If you want a better choice than self-made – one that is adequate for occasional use and camping  – there are out there. We’ve looked at several of the commercial units  – they are “OK” although not very substantially made and you can find them with goggle searches.  Please note that, as of this posts, there are no solar oven cookers that, in our view, are truly 4 season daily use cookers – like the grill on your deck –  save for our SUN GOD Solar Cookers (which is why we’re makin’ them!).

However,  if you just want to play around with the idea for cheap – this will give you an idea with one pot cooking:

inexpensive solar reflective cooker

Even though I personally like a larger more permanent solar oven, here is one that is doing well for people and has overall good reviews – it’s not really big but because it gets quite hot, it can do baked goods well:

Global Sun Oven

And for a good book with lots more on solar cookers, building them and the various types, this is about the best:

The Solar Cooker Book

Come by www.solarcookersnewmexico.com for lots more discussion and explanations.

Finally, DaiaSolGaia is building a Product Recommendation Store on Amazon for the best products and the lowest prices (often with super saver shipping) that we talk about in our blogs.  Take a look HERE.

Have a great day!